• Journal of Microbiology and Biotechnology
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• v.10 no.6
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• pp.881-884
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• 2000

A polymerase chain reaction (PCR) was performed to rapidly identify Lactobacillus plantarum from type strains and kimchi samples. The PCR experiments were carried out using specific oligonucleotide primer sets based on the 16S rRNA gene sequences of L. plantarum. The expected DNA amplificate of 419 bp was obtained when either purified DNA or whole cells of L. plantarum strains reacted with LP primers, yet not with any of the other strains. The PCR product was confirmed by DNA sequencing. Accordingly, since the PCR method used is simple, specific, and rapid, it will be useful for monitoring and evaluation L. plantarum in the mixed microbial population found in kimchi.

• Mycobiology
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• v.42 no.2
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• pp.158-166
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• 2014

In this study, bacterial strains were isolated from soils from 30 locations of Samcheok, Gangwon province. Of the isolated strains, seven showed potential plant growth promoting and antagonistic activities. Based on cultural and morphological characterization, and 16S rRNA gene sequencing, these strains were identified as Paenibacillus species. All seven strains produced ammonia, cellulase, hydrocyanic acid, indole-3-acetic acid, protease, phosphatase, and siderophores. They also inhibited the mycelial growth of Fusarium oxysporum f. sp. radicis-lycopersici in vitro. The seven Paenibacillus strains enhanced a range of growth parameters in tomato plants under greenhouse conditions, in comparison with non-inoculated control plants. Notably, treatment of tomato plants with one identified strain, P. polymyxa SC09-21, resulted in 80.0% suppression of fusarium crown and root rot under greenhouse conditions. The plant growth promoting and antifungal activity of P. polymyxa SC09-21 identified in this study highlight its potential suitability as a bioinoculant.

• Preventive Nutrition and Food Science
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• v.14 no.3
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• pp.265-268
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• 2009

Three-hundred bacterial isolates from a natural cheese were screened for the production of bifidobacterial growth factor by whey fermentation. Based on this screen, two whey samples fermented by strains designated as CJNU 0421 and CJNU 0588 were found to effectively stimulate the growth of a bifidobacterial strain, Bifidobacterium longum FI10564, by 1.6$\sim$1.7 fold compared to a control, in which non-fermented whey medium was added. The two isolates were identified to be Lactobacillus casei (99% identity) by 16S rRNA gene sequencing and named Lactobacillus casei CJNU 0421 and CJNU 0588, respectively. The whey sample fermented by CJNU 0588 did not enhance the growth of other bacteria such as Escherichia coli and Listeria monocytogenes, suggesting that the whey fermentation metabolites from the isolate could be used for the selective stimulation of bifidobacteria.

• Food Science of Animal Resources
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• v.28 no.3
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• pp.355-362
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• 2008

This study was carried out to assess the fermentation properties of lactic acid bacteria (LAB) isolated from bovine colostrum and effects of feeding fermented colostrum feed on the growth to piglet. A total of 427 colonies were isolated from bovine colostrum on the BCP plate count agar. These LAB isolated were subcultured in 10% reconstituted skim milk, and seven strain thereof were selected for their highest acid productions, and two strain thereof were finally selected for their excellent sugar utilization. These strains were identified as Streptococcus thermophilus and Streptococcus macedonicus based on l6S rDNA sequencing data, named S. thermophilus CNB-11 and S. macedonicus CNB-11 respectively. For fermentation profiles, sugar utilization, acid production and viable cell counts were excellent in S. thermophilus CNB-11 as compared with S. macedoniclts CNB-11 after 48 hour. The effect of feeding fermented colostrum feed 0.5% using S. thermophilus CNB-11 was investigated for growth rate, analysis of blood and incidence of diarrhea. 24 heads of piglets were divided into two groups: the experimental and the control of 12 animals each. The average growth rate in the pigs fed fermented colostrum feed was higher 16.73% compared with control diet (p<0.05). There were no differences in the concentrations of blood glucose, cholesterol, albumin and globulin in pigs fed fermented colostrum feed as compared with control piglets. Incidence of diarrhea was no in pigs fed fermented colostrum feed as compared with control piglets.

• Journal of Microbiology and Biotechnology
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• v.16 no.2
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• pp.193-199
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• 2006

Halotolerant spore-forming Gram-positive bacteria were isolated from the root, rhizosphere, and non-rhizosphere soil of Blutaparon portulacoides. The different isolates were characterized genetically using an amplified ribosomal DNA restriction analysis (ARDRA), and phenotypically based on their colonial morphology, physiology, and nutritional requirements. Three different 16S rRNA gene-based genotypes were observed at a 100% similarity using the enzymes HinfI, MspI, and RsaI, and the phenotypic results also followed the ARDRA groupings. Selected strains, representing the different ARDRA groups, were analyzed by 16S rDNA sequencing, and members of the genera Halobaeillus, Virgibacillus, and Oceanobacillus were found. Two isolates showed low 16S rDNA sequence similarities with the closest related species of Halobacillus, indicating the presence of new species among the isolates. The majority of the strains isolated in this study seemed to belong to the species O. iheyensis and were compared using an AP-PCR to determine whether they had a clonal origin or not. Different patterns allowed the grouping of the strains according to Pearson's coefficient, and the resulting dendrogram revealed the formation of two main clusters, denoted as A and B. All the strains isolated from the soil were grouped into cluster A, whereas cluster B was exclusively composed of the strains associated with the B. portulacoides roots. This is the first report on the isolation and characterization of halotolerant spore-forming Gram-positive bacteria that coexist with B. portulacoides. As such, these new strains may be a potential source for the discovery of bioactive compounds with industrial value.

• Microbiology and Biotechnology Letters
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• v.50 no.2
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• pp.245-254
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• 2022

Cellulases are a group of biocatalyst enzymes that are capable of degrading cellulosic biomass present in the natural environment and produced by a large number of microorganisms, including bacteria and fungi, etc. In the current study, we isolated, screened and characterized cellulase-producing bacteria from soil. Three cellulose-degrading species were isolated based on clear zone using Congo red stain on carboxymethyl cellulose (CMC) agar plates. These bacterial isolates, named as HB2, HS5 and HS9, were subsequently characterized by morphological and biochemical tests as well as 16S rRNA gene sequencing. Based on 16S rRNA analysis, the bacterial isolates were identified as Bacillus cerus, Bacillus subtilis and Bacillus stratosphericus. Moreover, for maximum cellulase production, different growth parameters were optimized. Maximum optical density for growth was also noted at pH 7.0 for 48 h for all three isolates. Optical density was high for all three isolates using meat extract as a nitrogen source for 48 h. The pH profile of all three strains was quite similar but the maximum enzyme activity was observed at pH 7.0. Maximum cellulase production by all three bacterial isolates was noted when using lactose as a carbon rather than nitrogen and peptone. Further studies are needed for identification of new isolates in this region having maximum cellulolytic activity. Our findings indicate that this enzyme has various potential industrial applications.

• Journal of Animal Science and Technology
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• v.66 no.2
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• pp.353-365
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• 2024

Rumen cannulation is a surgical technique used to collect rumen contents from ruminants. However, rumen cannulation surgery may potentially impact the composition of the rumen microbiota. This study aimed to examine the longitudinal alterations in the rumen microbiota composition of Hanwoo steers after cannulation surgery. In this study, eight Hanwoo steers were used; four steers underwent rumen cannulation surgery (cannulation group), while the remaining four were left intact (control group). Rumen samples were collected from all eight steers using the stomach tubing method on the day before surgery (day 0) and on postoperative days 1, 4, 7, 10, 14, 17, 21, 24, and 28, resulting in 80 samples (10 timepoints × 8 animals). The microbiota of all 80 samples were analyzed using 16S rRNA gene amplicon sequencing with Quantitative Insights into Microbial Ecology version 2 (QIIME2). There were no significant differences (p > 0.05) in all major phyla and most major genera representing at least 0.5% of total sequences across all 80 samples between the control and cannulation groups on the preoperative and postoperative days. However, while the alpha diversity indices did not differ (p > 0.05) between the two groups on the preoperative day, they significantly differed (p < 0.05) between the two groups on the postoperative days. Further, the overall microbial distribution based on both unweighted and weighted principal coordinate analysis plots significantly differed (p < 0.05) between the two groups on both the preoperative and postoperative days. Orthogonal polynomial contrasts indicated that major genera and microbial diversity in the cannulation group decreased following surgery but returned to their initial states by postoperative day 28. In conclusion, this study demonstrates that rumen cannulation surgery affects some major taxa and microbial diversity, suggesting that the rumen cannulation method can alter the composition of rumen microbiota in Hanwoo steers.

• Food Engineering Progress
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• v.21 no.2
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• pp.174-179
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• 2017

For preliminary molecular typing, PCR-based fingerprinting using random amplified polymorphic DNA (RAPD) is the method of choice. In this study, 14 bacterial strains were isolated from different Korean food sources, identified using 16S rRNA gene sequencing, and characterized through RAPD-PCR. Two PCR primers (239 and KAY3) generated a total of 130 RAPD bands, 14 distinct PCR profiles, 10 polymorphic bands, one monomorphic band, and four unique bands. Dendrogram-based analysis with primer 239 showed that all 14 strains could be divided into seven clades out of which clade VII had the maximum of seven. In contrast, dendrogram analysis with the primer KAY3 divided the 14 L. citreum strains into four clades out of which clade IV consisted of a maximum of 10 strains out of 14. This research identified and characterized bacterial populations associated with different Korean foods. The proposed RAPD-PCR method, based on sequence amplification, could easily identify and discriminate the lactic acid bacteria species at the strain-specific level and could be used as a highly reliable genomic fingerprinting tool.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.394-403
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• 2023

In the pursuit of sustainable and environmentally-friendly agricultural practices, we conducted an extensive study on the rhizosphere bacteria inhabiting soils that have been devoid of chemical fertilizers for an extended period exceeding 40 years. Through this investigation, we isolated a total of 80 species of plant growth-promoting rhizosphere bacteria and assessed their potential to enhance plant growth. Among these isolates, Burkholderia cepacia CD2 displayed remarkable plant growth-promoting activity, making it an optimal candidate for further analysis. Burkholderia cepacia CD2 exhibited a range of beneficial characteristics conducive to plant growth, including phosphate solubilization, siderophore production, denitrification, nitrate utilization, and urease activity. These attributes are well-known to positively influence the growth and development of plants. To validate the taxonomic classification of the strain, 16S rRNA gene sequencing confirmed its placement within the Burkholderia genus, providing further insights into its phylogenetic relationship. To delve deeper into the potential mechanisms underlying its plant growth-promoting properties, we sought to confirm the presence of specific genes associated with plant growth promotion in CD2. To achieve this, whole genome sequencing (WGS) was performed by Plasmidsaurus Inc. (USA) utilizing Oxford Nanopore technology (Abingdon, UK). The WGS analysis of the genome of CD2 revealed the existence of a subsystem function, which is thought to be a pivotal factor contributing to improved plant growth. Based on these findings, it can be concluded that Burkholderia cepacia CD2 has the potential to serve as a microbial fertilizer, offering a sustainable alternative to chemical fertilizers.

• Research in Plant Disease
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• v.30 no.1
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• pp.88-94
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• 2024

In July 2021, symptoms of soft rot were observed on the stems of Ficus carica in Yeongam, Jeollanamdo, Korea. To accurately diagnose the cause, infected stem was collected and bacterial strain was isolated. Among these, the pathogenic strain KNUB-08-21 was identified as Pectobacterium aroidearum through 16S rRNA gene sequencing and phylogenetic analysis based on the concatenated sequences of the dnaX, leuS, and recA genes. The affiliation of the isolate with this bacterial species was also confirmed by its biochemical characteristics obtained using API ID 32 GN system. Artificial inoculation confirmed the strain's pathogenicity in figs, causing significant damage to both stems and fruits. To our knowledge, this is the first report of P. aroidearum causing soft rot disease in F. carica in Korea.